Effect of Sugar Concentration on Escherichia coli and Zymomonas mobilis

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Ellen Jensen


This project is a precursor to studying chemotaxis in Zymomonas mobilis. Escherichia coli, the most studied bacteria, was used as the model to study chemotaxis in Zymomonas mobilis. However, the results from the sugar concentration experiment, in which six different sugars were used, clearly show that Zymomonas mobilis does not behave like Escherichia coli. Zymomonas mobilis grow best in 5-10% sucrose, and 5% fructose proves to be the second best sugar. The other sugars do not prove to be optimum in fostering growth. The optimum concentration of sugars such as dextrose, lactose and sucrose for Escherichia coli is well documented in the literature, in that "E. coli grows best in 1% sugar" (23). Finally, these experiments demonstrate that Zymomonas mobilis cells at different optical densities and phases of growth have different % motility and cell morphology.